Inverters are used, for example, in photovoltaic systems, abbreviated below to PV systems, to convert a DC current generated by a PV generator into an AC current suitable for feeding into a power grid. Most of the PV systems installed on buildings, in particular on residential buildings, are currently designed to feed into a public power grid. Situations can arise during operation of such a PV system, however, in which there is more locally produced power available than can be fed into the public power grid at that moment in time. In such a situation, a power supply company (PSC) which provides and/or looks after the public power grid can transmit a request to throttle down the PV system, as a result of which the maximum power to be fed in from the PV system is limited or any feed-in is completely prohibited. Electronic communication systems, for example, which are connected to the inverter of a PV system, are known for transmitting such a throttle-down request. The inverter can throttle down the fed-in power easily by varying the operating point of the PV generator either towards the open-circuit voltage or towards the short-circuit voltage of the PV generator. Renewable energy that can actually be used remains unused, however, in this situation.
Even when there is no throttle-down request from the power supply company, it may be increasingly attractive, because of a falling level of feed-in tariff, not to feed the energy generated locally by the PV generator into the public power grid but to use this energy to cover a private power consumption.